From f8f5c9bfacb2705750433681192eb1f3b9fdabd1 Mon Sep 17 00:00:00 2001
From: John Doty <john@d0ty.me>
Date: Tue, 9 Jan 2024 09:17:37 -0800
Subject: [PATCH] [fine] lets can be local or global

---
 fine/src/compiler.rs  | 25 +++++++++++++++++++++----
 fine/src/semantics.rs | 15 +++++++++++----
 2 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/fine/src/compiler.rs b/fine/src/compiler.rs
index aa640b74..a187aa00 100644
--- a/fine/src/compiler.rs
+++ b/fine/src/compiler.rs
@@ -29,6 +29,7 @@ pub enum Instruction {
     PushString(usize),
     PushTrue,
     StoreLocal(usize),
+    StoreModule(usize),
 }
 
 pub enum Export {
@@ -308,7 +309,10 @@ fn compile_identifier_expression(c: &mut Compiler, t: TreeRef, tree: &Tree) -> O
             assert!(declaration.index < c.function.args);
             Instruction::LoadArgument(declaration.index)
         }
-        Location::Module => Instruction::LoadModule(declaration.index),
+        Location::Module => {
+            assert!(declaration.index < c.module.globals);
+            Instruction::LoadModule(declaration.index)
+        }
     };
     c.push(instruction);
 
@@ -371,9 +375,22 @@ fn compile_let_statement(c: &mut Compiler, t: TreeRef, tree: &Tree, gen_value: b
     let environment = c.semantics.environment_of(t);
     let declaration = environment.bind(tree.nth_token(1)?)?;
 
-    // NOTE: Because this is a let statement I assume it's local!
-    assert!(matches!(declaration.location, Location::Local));
-    c.push(Instruction::StoreLocal(declaration.index));
+    let instruction = match declaration.location {
+        Location::Local => {
+            if declaration.index >= c.function.locals {
+                c.function.locals = declaration.index + 1;
+            }
+            Instruction::StoreLocal(declaration.index)
+        }
+        Location::Module => {
+            if declaration.index >= c.module.globals {
+                c.module.globals = declaration.index + 1;
+            }
+            Instruction::StoreModule(declaration.index)
+        }
+        _ => panic!("unsuitable location for let declaration"),
+    };
+    c.push(instruction);
     if gen_value {
         c.push(Instruction::PushNothing);
     }
diff --git a/fine/src/semantics.rs b/fine/src/semantics.rs
index 7c72a8d1..03746659 100644
--- a/fine/src/semantics.rs
+++ b/fine/src/semantics.rs
@@ -424,12 +424,19 @@ impl<'a> Semantics<'a> {
             None => Type::Error,
         };
 
-        let base_index = match parent.location {
-            Location::Local => parent.base_index + parent.declarations.len(),
-            _ => 0,
+        let (location, base_index) = match parent.location {
+            Location::Local => (
+                Location::Local,
+                parent.base_index + parent.declarations.len(),
+            ),
+            Location::Module => (
+                Location::Module,
+                parent.base_index + parent.declarations.len(),
+            ),
+            Location::Argument => (Location::Local, 0),
         };
 
-        let mut environment = Environment::new(Some(parent), Location::Local, base_index);
+        let mut environment = Environment::new(Some(parent), location, base_index);
         environment.insert(name, declaration_type);
 
         EnvironmentRef::new(environment)